SimpleChannelPool#notifyConnect() may leak Channels

[rkapsi]

Hey,

I just stumbled onto this one. The SimpleChannelPool#notifyConnect() method will leak Channels if the user cancelled the Promise.

private static void notifyConnect(ChannelFuture future, Promise<Channel> promise) {
        if (future.isSuccess()) {
            // This will leak the Channel if the Promise is complete
            promise.setSuccess(future.channel());
        } else {
            promise.setFailure(future.cause());
        }
    }

private static void notifyConnect(ChannelFuture future, Promise<Channel> promise) {
        if (future.isSuccess()) {
            // Possible fix
            Channel channel = future.channel();
            if (!promise.trySuccess(channel)) {
                release(channel);
            }
        } else {
            promise.setFailure(future.cause());
        }
    }

2016-07-19 14:14:48:400 EDT [32647,NIO-ConnectorThread-0,] WARN DefaultPromise - An exception was thrown by io.netty.channel.pool.SimpleChannelPool$2.operationComplete()
java.lang.IllegalStateException: complete already: DefaultPromise@78ba125f(failure: java.util.concurrent.CancellationException)
    at io.netty.util.concurrent.DefaultPromise.setSuccess(DefaultPromise.java:105)
    at io.netty.channel.pool.SimpleChannelPool.notifyConnect(SimpleChannelPool.java:159)
    at io.netty.channel.pool.SimpleChannelPool.access$000(SimpleChannelPool.java:42)
    at io.netty.channel.pool.SimpleChannelPool$2.operationComplete(SimpleChannelPool.java:134)
    at io.netty.channel.pool.SimpleChannelPool$2.operationComplete(SimpleChannelPool.java:131)
    at io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:514)
    at io.netty.util.concurrent.DefaultPromise.notifyListeners0(DefaultPromise.java:507)
    at io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:486)
    at io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:427)
    at io.netty.util.concurrent.DefaultPromise.trySuccess(DefaultPromise.java:111)
    at io.netty.channel.DefaultChannelPromise.trySuccess(DefaultChannelPromise.java:82)
    at io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.fulfillConnectPromise(AbstractNioChannel.java:300)
    at io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.finishConnect(AbstractNioChannel.java:335)
    at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:588)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:512)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:426)
    at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:398)
    at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:877)
    at java.lang.Thread.run(Thread.java:745)

[normanmaurer]

@rkapsi good catch! Let me come up with a fix

[normanmaurer]

@rkapsi PTAL #5557

[normanmaurer]

Fixed by #5557